Question

$frac{5}{7} +frac{6}{9}$

Answer 1

приводим к общему знаменателю:

$frac{5}{7}+frac{6}{9} =frac{5*9}{7*9} +frac{6*7}{9*7}=frac{45}{63}+frac{42}{63}=frac{45+42}{63}=frac{87}{63} =1frac{24}{63} =1frac{8}{21}$